Max Machinery 290 Trasmitter Interface - Manual (Page 6)

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6 IH 290-100-350 • rev. 2/2012 • ©2012 Max Machinery, Inc.
Flow Units
This field shows the units used for collecting the linearization data.
Analog Output
This sets both the output limits and the output scaling. Voltage transmitters can be set anywhere between -10V and
+10V, and current transmitters within the range of -20 mA to +20 mA. Because the transmitter receives a 2 stage
calibration at the factory, it is possible to change the analog scaling at any time without loss of accuracy or need to
re-calibrate. Note that the minimum and maximum output values are hard limits that the transmitter output will not
exceed. The Flow Minimum and Flow Maximum can be set to any desired measurement range both negative and positive
(the output span can even be set to a tight band such as 200 ccm minimum and 250 ccm maximum if you want very
high resolution and have a specific flow range that you are measuring).
Flow Calculator
This is simply a tool to allow the user to run sample values of either the flow rate or the output value. After entering
one field, the alternate field is then calculated based on the chosen analog scaling.
Meter Flow Direction
This field is set by the factory based on the mechanical design of each meter (CCW = counter clockwise). If the meter is
installed backwards for any reason, this field can be switched to correct any sign reversal. If bidirectional measurement
is not needed, this may be set to All Positive.
Flow Reversal Dead Band
On meters without a bidirectional output, there is a risk that momentary reverse flow will be output as if it was a positive
flow. To prevent this, the transmitter can be programmed with up to 100% of 1 meter revolution to act as a dead band.
For instance if you select 50%, any flow reversal that does not cause the meter to turn more than 1/2 of a revolution in
the reverse direction will be discounted and only net forward flow will be counted. If the meter turns more than the dead
band amount in the reverse direction the output will resume. For unidirectional configurations the default setting is 50%.